Electrical connectors have been provided in a wide variety of configurations for terminating multi-conductor cables such as integral flat or ribbon cables. With the ever-increasing miniaturization of electrical connectors and the ever-increasing numbers of wires in multi-conductor cables, electrical connectors of the character described have become increasingly complicated in order to accommodate relatively large numbers of conductors terminated in relatively small connectors. For instance, a ribbon cable may have conductors on close centerline spacing on the order of .025 inches. Connectors for such high density ribbon cables are used in a variety of applications, such as connecting disk drives in computers.
Most electrical connectors for terminating ribbon cables are of the insulation displacing termination type. These connectors generally include a housing having a mating face, an opposed cable-receiving face, and at least two rows of terminal-receiving passages extending between the faces. A plurality of terminals, most often stamped and formed of sheet metal material, are received in respective passages, each terminal having a mating portion toward the mating face of the housing and a generally U-shaped insulation displacement portion toward the cable-receiving face of the housing. Some form of secondary housing component, such as a cover, is provided for forcing conductors of the ribbon cable into the U-shaped insulation displacement portions of the terminals, with the cover embracing the ribbon cable between the cover and the cable-receiving face of the housing.
One of the problems with connectors of the character described immediately above, centers around the high density of the conductors in the ribbon cable. Because of the close spacing of the conductors, the insulation displacement portions of the terminals are arranged in two generally spaced-apart staggered rows with adjacent terminals located in opposite rows. Therefore, a conductor to be terminated in an insulation displacement portion located in a back row will necessarily have to pass between two insulation displacement portions located in a front row. The close spacing of the conductors and terminals may create problems and may result in shorting. One solution to this particular problem is to utilize the so-called "hill and dale" system which locates portions of adjacent conductors at the insulation displacement sections of adjacent terminals in different vertical positions or levels. However, molding the connector components for effecting this approach may be rather complicated and expensive.
More particularly, in a "hill and dale" system or connector, the cover has a cable-embracing face with a profile defined by a plurality of parallel conductor support channels. Each channel defines upper and lower conductor support levels arranged such that a lower conductor support level of one channel is between two upper conductor support levels of adjacent channels. The cable-receiving face of the connector housing has a similar multi-level channel configuration which is a mirror image of the configuration or profile of the cable-embracing face of the cover. Therefore, the channelled faces of the cover and the housing sort of "mesh" during termination of the conductors of the ribbon cable. Of course, it can be understood that major modifications may be required to the connector housing in order to provide the channelled cable-receiving face complementary to the channelled cable-embracing face of the cover. It would be desirable to provide a similar system wherein the main connector housing does not have to be modified, and modifications only need be made to the cover or secondary housing component. This invention is directed to that end.
Still further, "hill and dale" systems as well as other insulation displacement systems of the prior art, namely those systems which incorporate a mirror imaged cable-receiving face on the connector housing complementary to the cable-embracing face on the cover, have not proven to be precise and consistent in their terminations. This is due to the inability over time to mold plastic components with sufficient precision and consistency to accommodate such closely spaced terminals. According to another aspect of the invention, tooling can be used to force the conductors of the ribbon cable into the conductor support channels of the secondary housing component or cover and held thereinto by a novel conductor hold down means.